Open loop geothermal well systems typically depend upon the extraction of groundwater from a source e.g. a subsurface aquifer and then passing the water through a heat pump. Subsequently, the water is either disposed of at the surface or re-injected back to the aquifer through a dedicated secondary borehole located some distance from the extraction borehole. These systems suffer from corrosion and high maintenance costs as well as raising environmental concerns. Closed loop systems have advantages over the open loop systems since the working fluid circulates within the piping system between the surface and the interior of the well in a self-contained manner.